​Manchester United are tracking the performances of Napoli striker Dries Mertens 'very closely' according the Italian club's former sporting director, Pierpaolo Marino.

The 30-year-old has hit new heights at Napoli since the departure of Gonzalo Higuain, as he has netted 43 goals since the forward's move to Juventus, where he scored 28 goals last season alone which also saw him named as Belgium's Footballer of the Year in 2016.

Despite Mertens putting pen to paper on a new deal in May, which keeps him at Napoli until 2020, the striker is still receiving interest from a host of European clubs and Marino has claimed the Red Devils have shown interest due to his relatively cheap release clause.

In an interview with Tuttpsport, via ​Calcio Mercato, Marino explained: "The €28m clause is likely to be a low price even if he is 30.

"It turns out that United are following him very closely," he added.

30-year-old Mertens has continued to be a revelation for Napoli this season, scoring eight goals in nine appearances for the Serie A club - who remain undefeated in the league so far this season.

Manchester United are also in blistering form at the top of the Premier League, as Jose Mourinho's side have looked formidable in attack, and if Mertens was to be added to the fold the Red Devils would have a frightening amount of options up-front at their disposal.

Despite being 30-years-old, Mertens is one of Europe's leading forwards and with a €28m price-tag Mourinho may want to get his bid on the table in a quick fashion as United are unlikely to be the only side lurking for the striker's signature.

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